1. Field of the Invention
The present invention relates to a measuring apparatus for a passive element value using a current vector in which a passive element value is measured by the detection of the voltage vector drop at both ends of the passive element and current vectors flowing through the passive element when sine waves are applied.
2. Description of the Prior Art
Conventionally, the passive element value of a resistor, inductor, capacitor or the like has been measured by gain which varies according to the values of the passive elements or by a method of detecting changed characteristics thereof.
These kind of conventional measuring methods can have relatively accurate measurements in the case of measuring one element out of such elements as the resistor, inductor or capacitor. However, in the case of serial and parallel circuits comprising at least more than 2 kinds of passive elements, there arises a phase difference between the current and voltage. When the element value is measured by either one of current or voltage parameters, huge measuring errors are generated. Further, when an inductor element value is large, it is impossible to measure in itself due to generation of a reverse electromotive force.
Furthermore, when more than two kinds of elements are connected in a serial or parallel construction, it is impossible to measure more than two kinds of elements at the same time due to the above reason, that is, one of the kinds of elements is measured first and then the other kinds of elements are measured in sequence.
In other words, when a circuit connected in series with such two elements as resistor and capacitor, resistor and inductor, or capacitor and inductor, and the like, is measured by an impedance measuring method, it is difficult to distinguish respective element values because a combined impedance for the two kinds of elements is measured.
Therefore, in the case of a parallel circuit comprising two kinds of elements, the elements have to be measured individually.
By way of example, in case of a parallel circuit comprising a resistor and a capacitor, a constant current is applied to the parallel circuit via a measuring apparatus. The capacitor is thereby charged and the influence of the capacitor on the resistor is minimized, so that a voltage drop at the resistor is detected to thereby measure a resistor value, that is, an impedance.
Furthermore, apart from the resistor, a capacitor value, that is, a capacitance, is measured by utilizing a time constant wherein the capacitor is charged.
As seen from the foregoing, the resistance and capacitance are respectively measured by separate methods.
Specifically in case of a capacitor with a large capacity, it takes lots of time to charge, which inevitably causes a long time to measure.
Still furthermore, all the passive elements thus mentioned contain other characteristics in addition to basic characteristics intrinsic to the element.
In other words, a resistor basically has a resistant component expressed in the resistance. However, in a strict sense, a resistor contains an inductor or capacitor component at the same time in addition to the resistent component, and the same case applies to the inductor or the capacitor.
In this sense, the conventional measuring method has had a problem in that an accurate measurement can not be realized because the influences of the components other than the basic component have been disregarded in the measurement.
Accordingly, the present invention has been provided to solve the conventional problems, and it is an object of the present invention to provide a measuring apparatus for a passive element value using a current vector in which respective element values contained in the passive measuring element are measured by the detection of current vectors output during an application of sine waves to the passive measuring element.
It is another object of the present invention to provide a measuring apparatus for a passive element value in a serial or parallel circuit comprising more than two kinds of passive elements by which the passive element values thereof can be measured at the same time.